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Imagen de apoyo de  Major insect groups show distinct responses to local and regional attributes of urban green spaces = Importantes grupos de insectos muestran respuestas únicas a atributos locales y regionales de areas verdes
urbanas

Major insect groups show distinct responses to local and regional attributes of urban green spaces = Importantes grupos de insectos muestran respuestas únicas a atributos locales y regionales de areas verdes urbanas

Por: Manuel Eduardo; Latty Lequerica Támara | Fecha: 2021

Abstract: Urban green spaces vary in their local and regional attributes, and this variation can have contrasting effects on the ability of urban green spaces to support biodiversity. Here we assess the response of four insect taxa to urban development in Sydney, Australia, using a multiscale approach. We sampled four insect orders (Coleoptera, Diptera, Hemiptera and Hymenoptera) at 19 sites and employed a) multivariate analyses to test the responses of insect communities to environmental management regimes, and b) generalised linear models to determine taxa responses to urban green spaces at local and regional scales. We hypothesised that environmental management regimes (forest, urban forest remnant, and recreational park) affected the species composition of insect com- munities but found no evidence to support this hypothesis. Only species composition of hemipteran communities responded at this scale, with assemblages in urban forest remnants distinct to those in forests and recreational parks. Conversely, site attributes at local and regional scales had distinct effects on each insect group. While species richness of all taxa was positively related to local flower species richness, they exhibited variable re- sponses to regional attributes such as greenspace proportion and site area. The taxon-specific response to local and regional attributes of urban green spaces suggest that there is no silver-bullet for managing local or regional traits to promote diversity of major insect groups in urban areas. These results highlight the opportunities for managers and planners to develop unique and targeted taxon-specific interventions aiming to enhance urban insect diversity. Resumen: Los espacios verdes urbanos varían en sus atributos locales y regionales, y esta variación puede generar efectos contrastantes en su habilidad de soportar la biodiversidad. En este artículo evaluamos la respuesta de cuatro grupos de insectos al desarrollo urbano en Sídney, Australia, usando una aproximación multi-escala. Muestreamos cuatro ordenes de insectos (Coleoptera, Diptera, Hemiptera y Hymenoptera) en 19 sitios, y utilizamos a) análisis multivariados para evaluar las respuestas de las comunidades de insectos a los régimenes de manejo ambiental, y b) modelos lineales generalisados para determinar las respuestas de estos grupos de insectos en las escalas locales y regionales de los espacios verdes urbanos. Hipotetizamos que diferentes regímenes de manejo ambiental (bosque, remanentes de bosque urbano, y parques recreativos) tendrían efecto en la composición de especies de las comunidades de insectos, pero no encontramos evidencia que soporte esta hipótesis. Únicamente la composición de especies de las comunidades de hemípteros respondió a esta escala, con los ensamblajes de especies en los remanentes urbanos de bosque siendo significativamente diferentes a los ensamblajes de especies en las bosques y parques recreativos. De manera contraria, los atributos locales y regionales de los espacios verdes urbanos tuvieron efectos distintos en cada uno de los grupos de insectos estudiados. Mientras que la riqueza de especies de todos los grupos estuvo positivamente relacionada a la riqueza local de flores, todos los grupos exhibieron respuestas variadas a atributos regionales tales como la proporción de área verde y el área del espacio verde urbano. Estas respuestas específicas de cada grupo de insectos a los atributos regionales de los espacios verdes urbanos sugiere que no hay soluciones universales (en los regímenes de manejo ambiental) para promover la diversidad de insectos. Estos resultados demuestran las oportunidades que administradores y planeadores urbanos tienen para desarrollar intervenciones únicas y dirigidas a grupos particulares de insectos, para proteger la diversidad de los insectos en centros urbanos.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Major insect groups show distinct responses to local and regional attributes of urban green spaces = Importantes grupos de insectos muestran respuestas únicas a atributos locales y regionales de areas verdes urbanas

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Imagen de apoyo de  Educación e igualdad de oportunidades en las comunidades indígenas de Colombia

Educación e igualdad de oportunidades en las comunidades indígenas de Colombia

Por: Edda Patricia Izquierdo López | Fecha: 2021

Resumen: El derecho fundamental de las niñas y niños a la educación es más complejo de garantizar para las comunidades indígenas debido a que requiere lograr que las y los estudiantes accedan a una educación de calidad similar a la que reciben sus pares que les permita obtener las habilidades relevantes para competir en el mercado laboral e involucrarse en los desafíos de desarrollo económico y social que deben enfrentar sus propias comunidades; y, adicionalmente, que la educación impartida contribuya a preservar la existencia y forma de vida de la comunidad, que resalte el conocimiento tradicional y las prácticas culturales. Este documento, reseña la aproximación de Colombia a la provisión de educación para las comunidades indígenas -etnoeducación- a partir de una revisión normativa y el uso de datos administrativos del sector educación. Se encuentra que los docentes vinculados en concertación con las autoridades indígenas -etnoeducadores tienen menores salarios, formación académica y experiencia que el resto de docentes-. Adicionalmente, los estudiantes vinculados a establecimientos donde al menos 10% de los docentes son etnoeducadores, tienen peores resultados en el puntaje global, de lectura crítica y de matemáticas en las pruebas Saber 11. No obstante, una mayor proporción de educadores en las ETC y municipios parece tener un efecto positivo en la cobertura y disminuir la deserción.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Educación e igualdad de oportunidades en las comunidades indígenas de Colombia

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Imagen de apoyo de  Mechanical behaviour of bamboo at elevated temperatures – Experimental studies

Mechanical behaviour of bamboo at elevated temperatures – Experimental studies

Por: Mateo; Maluk Gutiérrez González | Fecha: 2020

Abstract: The growing demand for sustainable load-bearing materials drives the need for understanding the various design considerations these pose within the modern built environment. Engineered bamboo is a material with outstanding physical and mechanical properties, in addition to producing a minimum carbon footprint. However, extensive research is needed before engineered bamboo can be used with the confidence conferred to other more conventional building construction materials. When aiming for higher and larger bamboo-based structures, loadbearing behaviour during and after fire becomes a key consideration. This paper describes the outcomes of a comprehensive study conducted to understand the mechanical behaviour of bamboo (Phyllostachys pubescens species) at elevated temperatures; more specifically investigating the reduction of compressive and tensile strength, as well as the Modulus of Elasticity (MoE) up to 250 °C. Findings from this work show that at 200 °C, bamboo retains 20%, 42% and 70% of the compressive strength, tensile strength and modulus of elasticity at ambient, respectively. The results presented herein, which provide thorough understanding of strength and elasticity reduction at elevated temperatures, enable the development of stress-strain constitutive models that will constitute the basis for designing fire-safe bamboo structures.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Mechanical behaviour of bamboo at elevated temperatures – Experimental studies

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Imagen de apoyo de  Improving thermal comfort conditions in K-12 educational buildings in hot and humid climate: a case study in Cucuta, Colombia

Improving thermal comfort conditions in K-12 educational buildings in hot and humid climate: a case study in Cucuta, Colombia

Por: Diana Carolina; Ge Guerrero Yañez | Fecha: 2021

Abstract: The school buildings in Colombia are built based on geographical locations and regional construction systems. However, external weather conditions and building design can have a significant impact on the thermal comfort of students, which affects the academic performance and productivity. This paper investigates the thermal comfort performance for an educational building in a hot and humid city in Cucuta, Colombia, built under national guidelines. This school is a concrete structure without mechanical cooling. However, field observation discovered that 82% of the time students experienced thermal discomfort. To investigate causes and provide mitigation strategies, a whole building energy simulation is conducted. Design Builder is used to evaluate the indoor thermal conditions compared to outdoor data collected. ASHRAE 55 adaptative model is used for the evaluation. It is found that 79% of the time the thermal conditions are outside the acceptable range during the year. The effect of mitigation measures i.e., occupancy, roof insulation, and natural ventilation rates are investigated through simulations. It is found that occupancy and natural ventilation rate have a significant impact on the indoor temperature and relative humidity, and thus the thermal comfort. Passive design strategies are proposed in optimizing the school building design to meet ASHARE-55 requirements.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Improving thermal comfort conditions in K-12 educational buildings in hot and humid climate: a case study in Cucuta, Colombia

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Imagen de apoyo de  Analysis of the Prevalence and Incidence of Cleft Lip and Palate in Colombia

Analysis of the Prevalence and Incidence of Cleft Lip and Palate in Colombia

Por: Herney Alonso; Guarnizo Peralta Rengifo Reina | Fecha: 2020

Abstract: Objective: To analyze the population prevalence and birth prevalence of oral clefts in Colombia from 2009 to 2017. Methods: A cross-sectional study using information from the National Administrative Records of Colombia. The data came from 2 types of administrative records (Surveillance System and the Individual Registry of Service Provision) and the oral health national survey. Population prevalence and birth prevalence by type of cleft lip and/or cleft (CL/P) ratios were calculated using Poisson distribution for count data and to assess stationary tests on time series (Dickey-Fuller) and (Phillips-Perron) was used. Results: Population prevalence in Colombia was 3.27 per 10 000 inhabitants (95% confidence interval [CI], 3.21-3.32) and birth prevalence was 6.0 per 10 000 live births (95% CI, 5.67-6.35). Bogot´a have the highest population prevalence with CL/P. In the analysis of trends for the prevalence proportion by type of clefts in newborn babies with cleft, it was observed that the highest proportion was for babies with CLP. Cleft lip (CL) has increased from 17.4% in 2014 to 34.2% in 2017, cleft palate (CP) has decreased from 32.9% to 20.2%; and CLP changed from 49.6% to 45.5% in the same period. Conclusions: The population prevalence was 3.27 per 10 000 inhabitants. Births prevalence was 6.0 per 10 000 live births, and Orinoquia and Amazonia have higher rates than the national average. The administrative registers are adequate systems to know the behavior of oral clefts. The CL/P had a nonstationary trend during the period 2014 to 2017.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Analysis of the Prevalence and Incidence of Cleft Lip and Palate in Colombia

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Imagen de apoyo de  Population prevalence and trends of oral clefts in Colombia: analysis by departments

Population prevalence and trends of oral clefts in Colombia: analysis by departments

Por: Herney Alonso; Guarnizo Peralta Rengifo Reina | Fecha: 2021

Abstract: Objective: Determine the population prevalence and trends of cleft lip and / or palate (CL/P) by department for Colombia in the period 2009 - 2015. Methods: Prevalence study based on Individual Registry of Health Services in general population from 2009 to 2015. All people diagnosed with CL/P were included for all ages, type of diagnosis and any type of health services in the mentioned period. The prevalence rate was calculated by period and point for each year, for each department and according to the type of cleft. Stationarity on time series was evaluated using (Dickey-Fuller) and (Phillips-Perron), the trends and prevalence ratios were calculated using Poisson regression. Results: 15,225 people with CL/P were identified, where 53.3% were men. The national period prevalence of CL/P is 3.37 per 10 000 (IC95%: 3.3-3.4) with upward trend (PR = 1.34 95% CI: 1.0 - 1.8 p = 0.05) and non-stationary behavior. The national period prevalence of CL is 0.93 per 10 000, CP 1.17 per 10 000 and CLP 1.26 per 10 000, where CLP is sub classify into CLPu (0.83 per 10 000), and CLPb (0.43 per 10 000). At the departmental level, the highest CL/P prevalence is Guaviare (11.2 95% CI: 8.6 – 14.2), followed by Guainía (8.4 95% CI:5.4 – 12.2) and the lowest Quindío (0.49 95% CI: 0.3 – 0.7) Conclusions: In Colombia, the national period prevalence of CL/P is 3.37 per 10 000 with upward trend at national level indicates an increase on prevalence from 2009 to 2015.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Population prevalence and trends of oral clefts in Colombia: analysis by departments

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Imagen de apoyo de  Impact of dimensionality on nowcasting seasonal influenza with environmental factors

Impact of dimensionality on nowcasting seasonal influenza with environmental factors

Por: Stefany Brigetty; Miliou Guarnizo Peralta | Fecha: Ca. 2020

Abstract: Seasonal influenza is an infectious disease of multi-causal etiology and a major cause of mortality worldwide that has been associated with environmental factors. In the attempt to model and predict future outbreaks of seasonal influenza with multiple environmental factors, we face the challenge of increased dimensionality that makes the models more complex and unstable. In this paper, we propose a nowcasting and forecasting framework that compares the theoretical approaches of Single Environmental Factor and Multiple Environmental Factors. We introduce seven solutions to minimize the weaknesses associated with the increased dimensionality when predicting seasonal influenza activity levels using multiple environmental factors as external proxies. Our work provides evidence that using dimensionality reduction techniques as a strategy to combine multiple datasets improves seasonal influenza forecasting without the penalization of increased dimensionality.
Fuente: Biblioteca Virtual Banco de la República Formatos de contenido: Artículos
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Impact of dimensionality on nowcasting seasonal influenza with environmental factors

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Imagen de apoyo de  Recurring adaptive introgression of a supergene variant that determines social organization = Introgresión adaptativa recurrente de una variante de un supergen que determina la organización social

Recurring adaptive introgression of a supergene variant that determines social organization = Introgresión adaptativa recurrente de una variante de un supergen que determina la organización social

Por: Eckart; Pracana Stolle | Fecha: 2022

Abstract: Introgression has been proposed as an essential source of adaptive genetic variation. However, a key barrier to adaptive introgression is that recombination can break down combinations of alleles that underpin many traits. This barrier might be overcome in supergene regions, where suppressed recombination leads to joint inheritance across many loci. Here, we study the evolution of a large supergene region that determines a major social and ecological trait in Solenopsis fire ants: whether colonies have one queen or multiple queens. Using coalescent-based phylogenies built from the genomes of 365 haploid fire ant males, we show that the supergene variant responsible for multiple-queen colonies evolved in one species and repeatedly spread to other species through introgressive hybridization. This finding highlights how supergene architecture can enable a complex adaptive phenotype to recurrently permeate species boundaries.
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Recurring adaptive introgression of a supergene variant that determines social organization = Introgresión adaptativa recurrente de una variante de un supergen que determina la organización social

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Imagen de apoyo de  Effects of Curing on Photosensitive Resins in SLA Additive Manufacturing

Effects of Curing on Photosensitive Resins in SLA Additive Manufacturing

Por: Carmela; Civera Riccio | Fecha: 2021

Abstract: Different mechanical properties characterise the materials of 3D printed components, depending on the specific additive manufacturing (AM) process, its parameters, and the posttreatment adopted. Specifically, stereolithography (SLA) uses a photopolymerisation technique that creates solid components through selective solidification. In this study, 72 specimens were 3D printed using 12 commercial-grade methacrylate resins and tested under uniaxial tensile loads. The resin specimens were evaluated before and after curing. The recommended cure temperature and time were followed for all materials. The stress-strain curves measured during the testing campaign were evaluated in terms of maximum tensile strength, Young’s modulus, ductility, resilience, and toughness. The results reveal that the curing process increases the material stiffness and resistance to tensile loads. However, it was found that the curing process generally reduces the plasticity of the resins, causing a more or less marked brittle behaviour. This represents a potential limitation to the use of SLA 3D printing for structural elements which require some plasticity to avoid dangerous sudden failures.
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Effects of Curing on Photosensitive Resins in SLA Additive Manufacturing

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Imagen de apoyo de  Effects of the Manufacturing Methods on the Mechanical Properties of a Medical-Grade Copolymer Poly(L-lactide-co-D,L-lactide) and Poly(L-lactide-co-ε-caprolactone) Blend

Effects of the Manufacturing Methods on the Mechanical Properties of a Medical-Grade Copolymer Poly(L-lactide-co-D,L-lactide) and Poly(L-lactide-co-ε-caprolactone) Blend

Por: Mariana; Civera Rodríguez Reinoso | Fecha: 2021

Abstract: Biocompatible and biodegradable polymers represent the future in the manufacturing of medical implantable solutions. As of today, these are generally manufactured with metallic components which cannot be naturally absorbed within the human body. This requires performing an additional surgical procedure to remove the remnants after complete rehabilitation or to leave the devices in situ indefinitely. Nevertheless, the biomaterials used for this purpose must satisfy well-defined mechanical requirements. These are difficult to ascertain at the design phase since they depend not only on their physicochemical properties but also on the specific manufacturing methods used for the target application. Therefore, this research was focused on establishing the effects of the manufacturing methods on both the mechanical properties and the thermal behavior of a medical-grade copolymer blend. Specifically, Injection and Compression Molding were considered. A Poly(L-lactide-co-D,L-lactide)/Poly(L-lactide-co-#-caprolactone) blend was considered for this investigation, with a ratio of 50/50 (w/w), aimed at the manufacturing of implantable devices for tendon repair. Interesting results were obtained.
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Effects of the Manufacturing Methods on the Mechanical Properties of a Medical-Grade Copolymer Poly(L-lactide-co-D,L-lactide) and Poly(L-lactide-co-ε-caprolactone) Blend

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